The Dangers and Symptoms of Anal Cancer

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Anal cancer an insidious and growing concern among people living with HIV, predominantly gay and bisexual men. Symptoms can start out subtly at first, often with itching around the anus, much like the itching one might associate with hemorrhoids.

Later it can become painful or exhibit signs of bleeding. Eventually, a cancerous lesion can open, resulting in what is known as a malodorous drainage. Unfortunately, this is the point when most people finally decide to see a doctor, by which time the cancer is usually quite advanced.

Cancer is defined as an abnormal growth of cells that continue to multiply without the biological means to stop it. Anal cancer is a malignancy occurring in the anus, typically manifesting with a tumorous lesion. Anal cancers tend to develop in the mucosal tissue of the anus or in the anal margin that merges with the skin.

Anal cancer is of growing concern among people living with HIV. In the general population, anal cancer is considered rare, occurring in about one of 100,000 people. However, in men who have sex with men (MSM), the incidence climbs to as high as 144 cases per 100,000. Moreover, MSM who are HIV-positive is twice as likely to get anal cancer than MSM who are HIV-negative.

While we don't entirely understand why this is, it is believed that the chronic inflammation associated with HIV infection literally ages a cell before its time. When this happens, we will often see cancers developing in people with HIV 10 to 15 years before they would happen in the general population. Anal cancer is among the many cancers believed to be associated with this.

Risk Factors

There is a close association between anal cancer and the human papillomavirus (HPV), the virus which not only causes genital warts but is also associated with the development of cervical cancer.

In addition to HPV and HIV, commonly cited risk factors include smoking, multiple sexual partners, receptive anal sex, a history of hemorrhoids, and anal fissures or fistulas.

Signs and Symptoms

One of the things that make anal cancer so dangerous is that many people show few, if any, symptoms prior to diagnosis. More concerning yet, people will often delay seeing a doctor out of embarrassment, particularly if symptoms don't appear serious.

If symptoms are present they often include:

  • Warts on the anus or genitals
  • Sores or bumps around the anus or in the anal canal
  • Itching in and around the anus
  • Discharge or bleeding from the anus
  • Pain or pressure around the anus
  • Painful areas around the anus in the absence of visible bumps or lesions
  • Open sores around the anus that don't heal


Many experts now recommend routine anal cancer screening for people at high risk. Recommended tests include a yearly visual and digital exam, as well as a yearly anal Pap smear.

The latter takes a swab of cells from around the anus and examines them beneath microscope to identify cellular changes consistent with anal cancer. Abnormal Pap smears are typically followed with high-resolution anoscopy (anal scope) or biopsy.


The treatment of anal cancer depends largely on how advanced the cancer is. After an evaluation to determine the disease stage, a treatment plan is made with a board-certified oncologist.

In the case of a squamous cell carcinoma (SCC), chemotherapy and radiation are often recommended as first-line treatment. In the event adenocarcinoma, treatment may also include surgery.


Since HPV is considered the prime risk factor for the development of anal cancer, prevention should be largely focused on HPV avoidance. HPV vaccination is recommended for children and younger people, given in three shots over a six-month period. The Centers for Disease Control and Prevention currently recommends vaccination for the following groups:

  • All children 11 or 12 years of age
  • Teenage boys and girls who did not start or finish the HPV series when they were younger
  • Young women through the age of 26
  • Young men through the age of 21
  • MSM through the age of 26
  • Men with HIV who did not start or finish the HPV vaccine series when they were younger

High-risk individuals should be advised to use condoms with each and every sexual encounter and to reduce the number of sex partners.

In addition, anyone with a history of benign lesions should be monitored on a regular basis. An anal Pap can detect early cellular changes consistent with the development of anal cancer, allowing for early intervention and reducing the risk of disease progression.

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Article Sources

  • Centers for Disease Control and Prevention. "HPV Vaccines: Vaccinating Your Preteen and Teen." Atlanta, Georgia; access December 7, 2015.
  • Department of Veteran Affairs. "Anal Dysplasia and HIV: Primary Care for Veterans with HIV." Washington, D.C.; accessed November 25, 2016.
  • Goldstone, S. "Prevalence of and Risk Factors for Human Papillomavirus (HPV) Infection Among HIV-Seronegative Men Who Have Sex With Men." Journal of Infectious Diseases. 2011; 203 (1): 66-74.
  • Hleyhel, M.; Belot, A.; Bouvier, A., et al. "Risk of AIDS-defining cancers in HIV-1 infected patients (1992-2009): results from FHDH-ANRS CO4." Journal of the International AIDS Society.& November 11, 2012; 15(4).